1. Field of the Invention
The invention relates to devices for injecting plants, principally trees, with therapeutic liquid compositions such as pest control agents and nutrients. More particularly, it relates to devices providing for safe handling of toxic liquids in economical disposable containers within which a slight super-atmospheric pressure can be developed by the user which forces the liquid contents out of the container and into a feeder tube inserted into a tree trunk or other plant stem.
2. Description of the Related Art
The treatment of plants, especially trees, through injection of pest control agents and liquid nutrients has been known for some time. U.S. Pat. No. 3,286,401 to J. J. Mauget (xe2x80x9c""401xe2x80x9d) discloses an apparatus and method for such treatment wherein a container including two mutually slidable cups with spaced interlocks is used in combination with a feeder tube which at one end penetrates a frangible diaphragm sealing a container aperture; the other end is driven into the plant stem. The telescopically compressible cups provide a container with a variable interior volume partially filled with a liquid composition; the remainder of the volume is occupied by a gaseous substance such as air. Sealing of the liquid contents is effected by means of interference fits between the concentric, smooth walls of the cups. This arrangement does not always provide a reliable seal. Small variations in the concentricities and dimensions of the cups and/or in atmospheric pressure, as well as imperfections due to interior surface scratches can permit discharge between the mutually slidable walls of at least a portion of the contents during shipment or storage. Such leakage is especially likely to occur if the liquid has a high affinity for forming a capillary film. Since liquid compositions such as insecticides and fungicides used to treat plants may be toxic or otherwise harmful to humans, it is important that the possibility of leakage under shipment, storage and operational conditions be eliminated.
U.S. Pat. No. 4,365,440 (xe2x80x9c""440xe2x80x9d) to D. D. Lenardson discloses a similar telescopically compressible container with improved sealing. The container includes a pair of cup-like body portions having interfitting and mutually slidable sidewalls which telescopically engage through open ends of the portions. The upper portion (or closure) has a base and a depending cylindrical sidewall. The lower portion (or receptacle) has a base and outer and inner concentric, spaced cylindrical sidewalls determining an annular socket for slidably receiving the closure sidewall. The distance between two parallel rings projecting from the outer surface of the closure sidewall determines the extent of axial travel of the compressed container. The inner surface of the receptacle outer wall has a groove for successively receiving the rings. A ratchet-like ring configuration impedes reversible disengagement of the closure from the receptacle while permitting forward, telescopically compressible relative movement of the receptacle and closure. Compression of the internal volume of the container pressurizes the fluid contents, forcing liquid into a connected feeder tube. Although the seal provided by the ring-and-groove combination minimizes leakage, it is not totally hermetic.
U.S. Pat. No. 5,249,391 to J. A. Rodgers discloses a telescopically compressible binary container including an integrated liquid discharge tube. The container is intended to be non-disposable, in contrast to the ""401 and ""440 containers. The tube, which is slidably carried by a guide tube, resists being pulled from the guide tube when it is withdrawn from a tree upon completion of an injection operation. A resiliently deformable latch on one container section and a latch surface and cam means on the other container section engageable with the latch combine to provide locking in the compressed position. The container sections may be divided into separate volumes for storing dissimilar liquid and liquid or solid compositions. When a seal is ruptured by piercing means carried by the latch, the several compositions are mixed prior to entering the discharge tube.
Other devices for injecting plants which do not utilize the technique of self-pressurizing a compressible binary container are known. For example, U.S. Pat. No. 6,032,411 to V. K. Foust and U.S. Pat. No. 5,239,773 to G. D. Doolittle, Jr. disclose a two-piece syringe, U.S. Pat. No. 4,989,366 to T. A. DeVlieger discloses a device including a plunger and funnel, and U.S. Pat. No. 4,144,673 to D. H. Quast et al. discloses a gravity-fed multi-injector system.
It is a primary object of the present invention to provide a hermetically sealed, disposable capsule for injecting a plant with a liquid composition which will not leak during shipment, storage or during an injection operation.
Another object of the invention is to provide a telescopically compressible capsule which will remain locked when in a pressurized state.
Yet another object of the invention is to provide a capsule which is inexpensive to fabricate and suitable for mass production using thermoplastic injection molding.
Other objects of the invention will become evident when the following description is considered with the accompanying drawing figures. In the figures and description, numerals indicate the various features of the invention, like numerals referring to like features throughout both the drawings and description.
These and other objects are achieved by the present invention which in one aspect provides a plant injection dispensing capsule including a receptacle containing a therapeutic liquid composition and having a floor and a wall, orthogonal to the floor, terminating in a rim. The capsule further includes a cap having a central portion, a flexible portion symmetric about the central portion, and a circumferential edge hermetically sealed to the rim. The capsule further includes means for maintaining inward flexure of the flexible portion, thereby keeping the capsule pressurized.
In another aspect the invention provides a plant injection dispensing capsule including a receptacle containing a therapeutic liquid composition and having a planar floor and a cylindrical wall, orthogonal to the floor, terminating in a circular rim. The wall has an aperture proximate to the floor sealed by a dislodgeable membrane, and the floor has a channel proximate to the aperture. The capsule further includes a cap having a rigid central portion circumscribed by a living hinge including concentric annuluses bridged by stepped ridges orthogonal to the annuluses, and a circular edge hermetically sealed to the rim. The living hinge flexes inwardly when a downward force is applied to the cap central portion. The receptacle further includes an upwardly tapering spindle depending upwardly from the floor and having an outer surface. The cap further includes a polygonal-shaped socket, depending downwardly from its central portion, having a polygonal bore determined by a plurality of planar surfaces. The spindle is forcibly received within the bore when the living hinge is forcibly flexed inwardly, thereby pressurizing the capsule and creating an interference fit between the spindle outer surface and the socket bore surfaces which maintains the inward flexure.
In still another aspect the invention provides a plant injection dispensing capsule including a receptacle containing a therapeutic liquid composition and having a planar floor and a cylindrical wall, orthogonal to the floor, terminating in a circular rim. The wall has an aperture proximate to the floor sealed by a dislodgeable membrane, and the floor has a channel proximate to the aperture. The capsule further includes a cap having a rigid central portion circumscribed by concentric annuluses bridged by stepped ridges orthogonal to the annuluses, and a circular edge hermetically sealed to the rim. The cap flexes inwardly when a downward force is applied to its central portion. The receptacle further includes three posts depending upwardly from the floor. Each post has a hook-shaped upper portion with a planar lower surface, and a lower portion orthogonal to the floor. The cap further includes a cylindrical collar, depending downwardly from its central portion, having a distally tapering end portion with a circumferential groove determining an annular lip having a generally planar upper surface. The lower surface of each post upper portion engages the lip upper surface when the cap is forcibly flexed inwardly, thereby maintaining the inward flexure to keep the capsule pressurized.
A more complete understanding of the present invention and other objects, aspects and advantages thereof will be gained from a consideration of the following description of the preferred embodiments read in conjunction with the accompanying drawings provided herein.